Last week's striking Lords' debate on 42-day detention underlines again the value of an independent second chamber. This is only one of many recent issues where the House of Lords has defended natural justice and our ancient liberties – protecting rights to trial by jury; demanding fairness for war widows; blocking more night flights; stopping compulsory ID cards; and refusing to allow super-casinos to exploit Britain's poor.

But often, the Lords' common-sense voice is ignored. For example, it opposed home information packs, the changes in the voting system that have since led to fraud and 24-hour drinking. But in many cases like these, it was brushed aside. It was in tune with public opinion, but lacked the authority to press its case.

That makes part of the case for reform. Lords' powers must not be reduced. Tony Blair's rampant cronyism should never be repeated. Further change must strengthen its authority to ask the Commons to think again.

New Labour's policies on the Lords failed because they were politically driven and poorly thought through. Tony Blair expelled half of all Conservative and independent peers in the name of "democracy". Then, when he had been forced out by Gordon Brown, he admitted he never wanted democracy in the first place! He boasted he wanted to "give up patronage", but only after appointing a record 384 peers! Gimmicks, like so-called "people's peers", did nothing to bring the House closer to the people.

So where now? Some suggest the House should be entirely selected, handpicked by a statutory Appointments Commission. But would an all-appointed House be able to extend its authority? And others understandably ask, if the proposition is that nine men and women, meeting in secret, can choose the membership of half of our parliament, why not 60 million in an open vote?

Labour are edging closer to established Conservative proposals for a largely elected Senate, which would still retain the independent expertise of appointed cross-benchers. But all politicians would be elected by the people. To free senators from threat of de-selection and ensure independence from party whips, they would be elected for long terms and could not be re-elected.

There is much potential for consensus as we consider how what the elected House the Commons has voted for might be put in place. But there are still wide areas of disagreement. We argue any election should be direct, in smallish constituencies, based on our historic cities and counties, not by PR or lists in large, amorphous Euro-regions designed to give a permanent stranglehold on the House to the least popular political party.

We need greater clarity about the pay and conditions of would-be senators and the costs of reform. And what will happen to all Blair's appointees? If they stay for life, they could become a new army of Labour "backwoodsmen", trumping the votes of peers elected by the people.

The white paper is a useful step, but much more work has to be done. We have to see constitutional reform in the round. Reform is needed to strengthen both Houses. We cannot afford another botched change from New Labour.

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